Electrical connectors have become widely accepted as a preferred means for interconnecting the circuitry components of electrically operated products and equipment. In such applications, providing for the facile connection and disconnection of cable or wire through the use of connectors permits convenience of assembly and maintenance as well as versatility in design.
Connectors in current use are of diverse construction. However, a common arrangement includes a dielectric housing fitted with a plurality of stamped and formed conductive terminals to which insulated multiconductor cable or wiring may be electrically connected. Numerous terminal configurations likewise are available, suited to the specific requirement of the application. A preferred terminal in many applications is one which has the capability of establishing electrical contact with the conductors of the cable by displacement of the insulative coating of the conductors, obviating the need to perform the separate step of stripping the insulative coating.
A wide variety of insulation displacement terminals are known in the art. Generally, these terminals provide a narrow slot which receives an insulation covered wire, severs the insulation covering of the wire in the process, and establishes, automatically, an electrical connection between the terminal and the central core of the wire. This is contrasted with the self-piercing type of terminals which usually have sections in the form of teeth that pierce the insulation and enter the metallic core when the terminal is clinched or secured to the wire.
Both the self-piercing and insulation displacement terminals, as previously known in the art, suffer from a number of disadvantages. First, both techniques have limitations in terms of the acceptable wire dimensions which may be used in connection with a specific terminal. In addition, many terminals generally require a transverse actuating force to be applied in order to establish the electrical connection. That is, a force must be applied transversely of the length of the wire, requiring the wire to be accessible to the transversely applied force at the terminal. Where it is desired that the terminals are prefitted into the connector housing prior to wire termination, the requirement of transverse terminal accessibility prevents the close spacing of a plurality of connections. This condition is particularly limiting where multiple rows of circuit connections are desired.
The above problems have been solved by very effective prior art terminals shown in U.S. Pat. Nos. 4,512,619 to Dechelette, dated Apr. 23, 1985, and 4,955,816 to Roberts et al., dated Sep. 11, 1990, both of which are assigned to the assignee of this invention and which are incorporated herein by reference. Briefly, those patents show novel terminals wherein collapsible conductor engaging portions are collapsed inwardly to displace the insulation of an insulated wire and establish conductivity with the core of the wire upon the application of forces on the terminal in a direction generally parallel to the longitudinal axis of the terminated insulated wire. This invention is directed to further improvements in such unique terminals.
Specifically, electrical connectors utilizing insulation displacement terminals of the character described above have been miniaturized drastically in recent years to conform with the corresponding miniaturization of circuits and electrical components. Despite the smaller dimensions, it is necessary for connectors to consistently provide high quality electrical connections. Even small improvements in performance have become very significant in the electronics industry. With the invention herein, collapsible portions of the terminal not only displace the insulation of the insulated wire to establish conductivity with the conductive core of the wire, but the collapsible portions of the terminals provide increased contact areas with the conductive core. In addition, strain relief is provided for the collapsible portions of the terminals, all in response to collapsing the terminal by the application of a force on the terminal in a direction generally parallel to the longitudinal axis of the insulated wire.